Fitting a CD8 Engine in chassis-Horizontal fore/aft?

[Gunsmoke]

I am getting ready to set a '31 Deluxe CD8 engine in the chassis of my barnfind Roadster. The intermediate cross member it is supposed to sit on at rear (on a rubber center steady rest) is missing, and the 2 rear engine mounts which bolt to bell housing were missing when I got car (a PO had installed a Flathead '47 Cadillac engine).

 

I now have the 2-rear mount outer pieces which bolt to the side rails in original holes. However I need to make the inner parts of these 2-piece brackets, pieces which rise up to suit proper location of bellhousing. So my question is: Does the engine sit more or less horizontal fore/aft when installed originally? I have 3/16" rubber washers to put under front mounts, so front should be just where it belongs. My plan is to set engine with bell attached in chassis, temporarily bolt front and cearefully lower rear until fore/aft alignment is right and then make the bellhousing brackets and crossmember to suit. These are pictures of the required crossmember and side brackets for your ease of understanding the query.  

[JACK M]

Not specific to your particular application, BUT.

You want the centerline of the crank shaft to be parallel to the pinion shaft on the rear end.

They don't have to be in line so to speak, but need to be parallel.

This all needs to be done with an average load on the chassis.

[Taylormade]

Before you do anything else, get the rubber in those mounts replaced. Now and Then Auto does a nice job for a reasonable price. That old, rotted stuff is likely to tear out under any hard use.  My 29 Plymouth had a setup similar to yours, although the mounts connected directly to the frame and the bellhousing.  There was no separate piece between the mount and the belhousing.  I couldn't find a photo or lube chart for a CD-8, but a chart for a 31 Dodge 8 shows the mounts going directly from the frame rail to extensions on the bellhousing.  I think those extensions are cast into the bellhousing.

 

This is a chart of the Dodge 8.

 

 

My Plymouth mounted the same way.  I remember it was quite a job getting that bellhousing in between those mounts on the frame!

[Gunsmoke]

The photo of brackets I showed above are from a colleague in Maryland. The rubber in my side mounts seems in very good condition and brackets have no rust. The CD8's have a heavy crossmember under rear of oil pan as shown and it rests engine weight on a rubber steady rest/pad. I have no idea if it was intended to take full weight of back end of engine/transmission (perhaps 300 lbs) and then side brackets were tightened or what the ideal assembly process was. I gather this method evolved over a series of attempts to eliminate/reduce vibration. By this method, the side mounts are less under load. They keep engine in place and assist in preventing vibration, as well as stiffening the chassis generally. Similar to DC8 Dodge, they bolt to ends of bell as shown in above illustration. My thinking now is that I will bolt up bell and the transmission and align the output shaft with centerline of hole in crossmember. and pull a string through to rearend and see what alignement looks like. The parallel rule makes sense so U-joints are working equally and whole assembly is more or less balanced and in-line.  

[Taylormade]

Can you get accurate measurements from the colleague in Maryland and make up a set for your car? Or perhaps he will lend you his for use as a pattern.

My 32 Doge DL has a similar crossmember with a rubber pad very much like yours. My car does not have the bell housing mounts, there is another rubber mount that attaches to the transmission and a rear mount bolted to the frame, providing true "Floating Power."

[Rusty_OToole]

Usually the engine tips down to the rear about 7 degrees. You can check this by putting a level on the intake manifold where the carb sits, they make the manifold at an angle so the carb sits level. The chassis has to be level for a true reading.

[Gunsmoke]

Thanks Rusty for the tip regarding the 7 degrees and the carb mount. My barnfind has been substantially modified, and while I am trying to bring it back to something resembling original '31 CD8 Roadster specs, it is quite a challenge since so many parts are missing and what is left is also altered here and there. When I get the dimensions from Rob in Maryland for the brackets, I will make some and hopefully when installed will allow engine to sit where you suggest, with a slight tilt to rear. 

[Rusty_OToole]

Check the engine with a level on top of the carb or manifold, I am more used to newer engines, do not know the exact angle of yours if any but 7 degrees is typical.

Edited June 20, 2015 by Rusty_OToole (see edit history)

[Gunsmoke]

I bolted the intake manifold to the block and sure enough there is a slight angle difference between carb mounting spot and alignment of head/block, somewhere around 5 degrees down toward rear. I'm thinking I will set chassis level on 4 jack stands (difficult to know where level is on these chassis fore/aft as virtually all of side rails are curved. Would try using axle ends, but car has no load on chassis so springs are not under load. I think the short stretch of frame where door opens is normally horizontal so door verticals are plumb. Once jackstands are level all around, I'll set block on rubber washers on front mounts and lower it gently until carb mounting face is horizontal and see if that looks about right. I'll then put an adjustable jackstand under oil pan support bracket and assess next steps. The confirmation measurements from Maryland Rob (Vintchry) will seal the deal.  

[Taylormade]

Not trying to beat a dead horse here, but do you have any of the front motor mount?  This is usually a support that straddles the frame and has a rubber pad that sits between the mount and a tab on the engine - usually just above the timing gear cover.  This front mount is necessary for this rubber mounted system to work properly.  If you mount the front of the engine in a solid mount, the two rear rubber mounts will be fighting it and this could twist your front mounting bolts off.  I know it's a pain, but if you could find a parts car with these parts, your life would suddenly become much simpler.  As to that center crossmember, mine was actually bolted onto the frame, although a friend of mine who also has a 32 Dodge found that his was riveted on.  His was made much later in the production run.  Trying to find some of this stuff can drive you crazy at times, but for the rubber mount system to work properly, you need all mounting points to be set up correctly, and that is stating the obvious as I'm sure you're aware of the problem.  Maybe try an ad on the H.A.M.B site, a rodder may have gutted his frame and still have some of the original parts you need.

[Gunsmoke]

As indicated in opening post, the original front engine mount points are still on the chassis (see pic, with some additional steel plate which was added by a PO, since removed), so other than rubber washers (which I am told should be about 3/16" thick, one above and one below the mount with steel washers top and bottom), that end should be OK. I've secured the siderail brackets firmly to rails (without the bell bracket part), and plan to set engine and be3ll housing in place to see just how things look. The frame has had a lot of modifications, but generally straight, and other than the missing oil pan support crossmember, most parts are with car or can be easily made. Hope to lower engine into car tomorrow, I'll post a picture if it looks OK

[Taylormade]

Wow, the PO really chewed up your frame.  I found these shots of a CD8 motor.  They show the cradle (the black support sticking out at the front of the motor on each side) I was talking about and it appears it bolts to your mounts, although I'm not sure what that inner hole in the mounts is for as there seems to be only a top and lower bolt on the engine cradle.

 

 

 

If there is indeed a two bolt mounting setup for each mount, I'm not sure how the rubber washers would work since you have a vertical and horizontal axis that would work against each other.  All Chrysler products I have seen and restored (1929 Plymouth, 1932 Dodge, 1948 Plymouth, 1950 Dodge) have this front support firmly bolted to the frame with no rubber washers.  The place where the support attaches to the motor would have a rubber pad that provides isolated movement between the front crossmount and the motor.  Of course, your Chrysler may have had a different design as I can't tell from the photos how the crossmount is actually attached to the motor.

 

Were the front mounts shown in your photo used to mount the Cadillac flathead?  If so, they may be later additions and not positioned correctly for your original engine.  All mounts from this era that I have seen were riveted to the frame.  If yours are welded on, they are probably not the original mounts.  Good luck dropping the motor in, I hope it goes well!

Edited May 26, 2015 by Taylormade (see edit history)

[Gunsmoke]

Firstly, the Cadillac Flathead with a LaSalle transmission was mounted much further rearward, and had its own homemade mounts/crossmembers, rough and since discarded. The engine mounting points shown in pictures are original and riveted to chassis. The '31 Deluxe CD8 Engine I have has the same yoke/cradle affixed to timing chain area as shown in the picture you attached. It is bolted solidly to block, as originally designed. As you may know, when Dodge (1930) and later Chrysler (1931 forward) began using the straight 8, vibration problems were a technical and marketing issue. I understand the early Dodges (2&7/8" bore) relied on the 2 front mounts and the 2 rear mounts only, and later added a transmission mount as well. Chrysler introduced the intermediate cross member and later stiff extra "crossmember brackets" and a " steady rest" to try and eliminate the vibration issue, especially as the horsepower increased as bore rose to 3.25", and higher cruising speeds were possible. Eventually they went to a different support up front, the so called pendulum system. In '31, the 4 point engine mounting and intermediate braced crossmember (effectively a 5th point mount) allowed the engine to substantially stiffen the rather weak ladder style chassis, which was prone to twisting. Later Chrysler went to the X-frame which solved the twisting problem somewhat and alowed a 3 point mounting of engine. TMI perhaps, but knowledge of these technical developments has been hard to find for me, and thank goodness we have some knowledgeable Chrysler/Dodge guys who have been willing to share this info with me. 

 

I expect nailing down the engine in its final proper spot will require some precision fitting of the 3 rear mounting parts, the 2 side pieces and the steady-rest, (to achieve minimum vibration, good alignment with rearend, and effective stiffening of chassis), and even then the original vibration issue will likely still show up at 80MPH!!

[Taylormade]

Looks like you have a good handle on the situation.  Sorry for my rather long-winded descriptions.  My Dodge is a six and the vibration problems were obviously not as problematic as with the eight cylinder cars.  It also has the X-frame and boxed front rails (from the factory) which makes for a much stiffer frame and the opportunity to mount the motor differently.

 

 

 

Let us know how your installation progresses.

[Gunsmoke]

That is a very nice frame (year/model?) and looks strong. I was surprised at how "flimsy" the CD8 ladder style frames are. For a 124" WB car, there was not much to prevent twisting except the engine, and for sedans, perhaps the body as demonstrated in some of the marketing videos of the time. The crossmembers are of pretty thin material. I know many european race-bred cars used a 4 point solid mounted engine as the primary means of eliminating chassis twisting. 

[Taylormade]

It's a 1932 Dodge DL (six cylinder) frame - nice and beefy.  It's a sedan and the body has no cross supports between the doors as the frame is stiff enough to keep the body square.  The body also is channeled down over ther frame rather than sitting on top of the frame rails as in earlier models.  I suspect the very flexible ladder frames proved too filmsy for the Chrysler rubber mounted engine system and the X-frame design was introduced to remedy the situation.

[keiser31]

Just to inform....the 1931 was the first year for the body to be lower than the top of the frame.

[Gunsmoke]

I found the proper bell housing bracket for CD8's (thanks Rob) and fitted them in chassis as shown. For comparison, I placed the Dodge bracket beside it and as seen the CD8 bracket is about 2" higher. I suspect engines in Dodges and Chryslers were near same height above ground (in order to clear suspension, align with rearend etc, but Chrysler mid- chassis was 2-3" lower so engine mounts are quite different front and back. I also show the tubing I plan to use in making the rear cross member which fits under oil pan (see onpening topic photo).

 

I have the Deluxe CD8 engine fitted with many of its accessories and plan to drop the assembly into the chassis next week to see how things fit. Will likely have to do a few tweaks to bell brackets as chassis has been narrowed about 1/4" in this area by PO instaling new reinforcing steel plates inside original frame rails.  The bellhousing shown is from a '30/'31 Dodge 8, I think Chrysler bells may have been deeper to take larger pressure plate, not sure?

Edited June 12, 2015 by Gunsmoke (see edit history)

[Gunsmoke]

The Deluxe CD8 engine has finally settled in where it belongs, in my '31 barnfind CD8 Roadster chassis. Was a bit of a thrill I must say to see it fall into place, the original engine was probably removed about 70 years ago, circa 1945. Thanks to Rob for the engine and rear outriggers, everything bolts up amazingly close, considering all the modification the PO's made in fitting a Caddy flathead and an OHV Ford V8 over the years.The intermediate cross member under engine is missing, so now that I can see final dimensional requirements for its manufacture, I will make it. Engine is sitting on an axle stand at rear for now. The lack of the missing crossmember resulted in the chassis spreading outward 1/4" on passenger side bottom, not a big deal, I will try to pull it back at the bottom using a couple pipe clamps, but if it does not want to move easily, I'll leave as is and make crossmember a tad longer. This is my Father's Day present to myself, all the best to you other Dads out there.

[Taylormade]

Looks like you're making real progress. Not to be a nabob of negativity, but does the engine slant a bit too much to the rear? It's a bit hard to see if the frame is level in pictures, but I know my two Dodges and my two Plymouths had/have engines pretty much level with the ground. It may just be the way the photos are shot and not a problem at all. Considering what you have to work with, outstanding job.

[Gunsmoke]

Camera was tilted a bit, so engine slope is not as much as it appears, I calculate it as about 2-3 degrees, and it results in crankshaft end lining up well with centerline of driveshaft hole in crossmember, and path to rearend. A previous poster indicated these power plants were sloped down towards rearend, so I'm thinking it's close. Since the original holes are in the siderails for the 2 piece rear mounting brackets, I'm inclined to asume the engine/ chassis angle is near spot on. Once I lower everything off of jack stands, I'll still be a bit in the dark, I don't know how close the front and rear springs are to original arc specifications, the front wheels are 15", rears 16" etc, and of course, adding the body and the rest of the weight may change front/back pitch. As near as I can gather, a degree of variation is not crucial other than perhaps visually the carb may sit slightly off vertical? I appreciated your careful, knowledgeable and thoughful advice and interest. Hope to put transmission and rest of drivetrain in place soon, then will know how close things are.